@ramsey Usually for i.m. or i.v. Ketamine you start with an intense two weeks or so initial round and continue with treatments about once a month or so.
Highly depends on how well or not it works for you individually.
Ketamine alleviates depression symptoms within literal minutes and helps brain heal longer term so over time depression flares should be less strong.
I recommend something with guidance so you can make sense of what happens during treatment (out of body feeling/hallucinations).